This R03 grant, in response to NIDA's PAR-00-059 "Small Grant Program," will importantly support the implementation of exploratory research that incorporates a novel and extremely fine-grained approach to the study of nicotine and human performance. This innovative methodology uses electromyography to dissociate the central (cognitive) and peripheral (neuromuscular) processing related to the successful completion of a variety of reaction time tasks. To further discriminate at what level of the central processing stream nicotine is most likely to have an effect, a basic chronometric approach to studying information processing will be incorporated. This chronometric approach will allow for the independent examination of each of the three theoretically nonoverlapping information processing stages which include stimulus identification, response selection and response programming. This methodology provides the opportunity to investigate nicotine's effects on the time between the initiation of the stimulus and the initiation of the motor response (central processing) as well as the time delay between the initiation of the motor response and the actual movement or button release (neuromuscular processing) during a variety of reaction time tasks. This paradigm has been shown to be sensitive to a number of variables such as: intensity of stimulus, number of response alternatives, complexity of movement, age, physical activity and pathologies, but has yet to be used to investigate the affects of nicotine on movement preparation, initiation and execution. These methodologies are well grounded in the field of Motor Learning and Cognitive Psychology, and will be a definite addition to the literature in regards to nicotine effects on human performance. Moreover, the methodologies offered herein could have clinical payoffs in populations, such as Parkinson's disease, Huntington's disease and other pathologies where the planning of movement is thought to be intact, but the initiation of movement may be compromised. This laboratory-based project uses cigarette smokers to better understand how nicotine affects the individual components (pre-motor and motor time) of a variety of reaction time tasks. This disassociation of central and neuromuscular components within a reaction time paradigm offers a substantial positive deviation from previous research utilizing only simple or choice reaction time methodologies because it may be that individual task components are influenced differentially by nicotine, which would not be evident if only a single, summary measure of reaction time was used. This study will be accomplished by systematically varying experimenter supplied nicotinised and denicotinised cigarettes while administering a variety of subjective, physiological and performance measures under double blind, placebo controlled conditions.